Infected bacteria from fish on sponge filters

[ganesan]

I was just thinking if one has been having disease outbreak in the quarantine aquarium with finrot, white spot etc and some fish die while some made it. The sponge filter has been running continuously in this aquarium and is alright to remove the same sponge filter after squeeze cleaning it in the quarantine tank water and placing the sponge filter in another display main aquarium so that it has bacteria and would quickly bring down nitrite and nitrate in the display tank when new fish are added. Is there any chance of some bacteria remaining in the sponge filter which could harm the newly added discus in the display aquarium.

[dspeers]

The situation as described would almost guarantee cross contamination (CC). People go to great lengths to avoid CC, keeping seperate nets, agressively washing hands up to elbows when moving between tanks, seperating the QT into another room on the off chance there is an aerosol CC (think COVID). Only squeeze rinsing a sponge in order to preserve the nitrifying bacteria almost guarantees that some pathogens stuck on the surface of the sponge will survive to contaminate tank next.

[ganesan]

Thanks I never thought cross contamination was so serious. Yes I was aware that it is better to have separate nets,hoses,for a discus fish aquarium besides washing hands but I didn't think about cross contamination through sponge filters.

[CliffsDiscus]

There was a locaL breeder that kept having break out of deseases. He said that the sponges were clean and hanged out air dry.
He found out that the sponges were still damp way inside, even the outside was bone dry.

[brewmaster15]

Boiling sponges if you want to re-use them and they are from questionable tanks is a good method to reasonably safeguard against cross contamination. You will lose your biofilter but if a sponge has been in a tank without a source of food for the beneficial bacteria to consume for a while...theres not much there really to lose.

I would not trust a sponge that was from a sick tank to be safe after drying because of the reason that Cliff said and because some bacterias could be resistent to drying out by being enveloped by a water film. Most of the pathogenic bacteria we deal with are not spore producing.(Spore help bacteria populations survive drying out) but they can be pretty hardy like Edwardsiella tarda. I think Mycobacterium like Mycobacterium marinum .. a very serious and dangerous pathogen does produce spore (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906719/). Incidentally both Edwardsiella tarda and Mycobacteria marinum can infect humans. I also would not doubt other pathogenic bacteria have survival strategies we do not fully understand. Lastly pathogenic fungus can also survive drying through spore formation... (https://www.sciencedirect.com/science/article/abs/pii/S0044848621012163)

Better safe than sorry. If you absolutely must reuse filter material from a questionable tank.. boil it first or if it is something like ceramic noodles.. bleach it.

Hth,
Al